Usually, you would be asked to pick one or two. But with hose barbs, you get all three. Of course, it’s not as easy as pulling any hose barb off the shelf. Careful consideration must be given to multiple variables such as tubing diameter, tubing material, the fluid being handled and the construction and material of the hose barb itself. Let’s take a look at the three factors that define hose barbs.
Simple.
A hose barb truly is simple. It’s a fitting or coupling termination with one or more continuous ridges or bumps that grip the inside diameter of a tube to seal the connection.
Installation of tubing on a fitting or coupling with a hose barb is simple as well. Just install the tubing by pushing it into a coupling with a hose barb termination. The tube will expand over the barb. Gripping and sealing occurs as the tube tries to relax to its original inside diameter behind the barb.
Dependable.
For most applications, one hose barb on a fitting or coupling provides 100% of the sealing and most of the holding force for a tubing termination. Certain applications or tubing quality require a tie or clamp to provide additional holding power. While compression and screw-on fittings have their place, the barbed fitting remains the dominant system for connecting flexible tubing.
Inexpensive.
For such a versatile and effective solution, fittings or couplings with hose barb terminations will probably be the least expensive component in your system. Depending on the application, the hose barb fitting or coupling will be made from metal or plastic. Metal hose barb fittings or couplings tend to be used for handling certain chemicals and compounds or where the environment is harsh.
It’s also important to make a distinction between inexpensive and cheap. In making a plastic hose barb fitting, a mold opens and closes as each piece is produced. In this process, a parting line is created, this seam produces a slight imperfection on the plastic part where the two halves of the mold meet. This parting line invites leaks and system failure. Parting lines are especially prevalent with a poorly molded part or where the manufacturer has skimped on tooling investment or maintenance.
When the connection is mission-critical, look for parting line-free hose barbs. Because of the advanced manufacturing process, they are a little more expensive but well worth it for peace of mind.
Other things to keep in mind:
Hose barbs on fittings and couplings come in many shapes and sizes. Slope and depth of the barb, sharpness of the gripping edge, number of barbs, and spacing of barbs are all factors that contribute to the gripping and sealing ability of hose barbs. The internal diameter of the tube, flexibility of the tube material, and the intended application all factor into the decision on which fitting or coupling to choose for the job. It’s always a good idea to test a hose barb fitting or coupling with your exact tubing and application parameters.
The right number of barbs. This is dependent on the application and type of tubing used. The reason is found not so much in the geometry of the barb, but in the spacing of barbs and the behavior of the tubing. Often a single barb is adequate. This is not to say that multiple hose barbs on fittings and couplings are bad. For example, if barbs are spaced so that the tubing relaxes between each barb, then each additional barb can provide more grip.
A key component of determining tubing terminations is the accuracy of the inside diameter of tubing. Given the inherent variability in tubing and hose material, it is important to carefully select a fitting or coupling that meets the inside diameter specification of the tubing being used. The rubber hose and plastic tubing available today all exhibit different levels of flexibility, a factor that plays a large part in how well a connection performs. In general, the softer the tubing, the more likely that a hose barb type fitting or coupling is appropriate for the application.
Understanding pull-off resistance. When a tube is pulled, it tends to contract and grab more tightly. A particular fitting or coupling will therefore exhibit different tensile strength characteristics for different sizes and grades of tubing. If the barb is too sharp and the tubing is very soft, enough pulling and vibration could cut the material and cause leaks and failure. On the other hand, a shallow or rounded barb mated with very stiff tubing may allow a tube to disengage with minimal pulling force.
Understanding blow-off resistance. Spikes in pneumatic or hydraulic pressure tend to make tubes expand, potentially loosening the grip of the barb. For high pressure applications, the shape and arrangement of barbs and the relative flexibility of the tubing determines how the connection will perform under expansion of the tubing material.
Remember to consider the ease of installation. Shape and placement of the barb(s) on fittings and couplings combined with tubing flexibility determine the force required for the technician to connect the fitting to the tubing. Remember, if it is too difficult to push tubing onto the fitting, the tubing may not grip properly and open the possibility for leaks and failure.
To clamp or not to clamp? While the hose barb effectively grips the inside of the tube, clamps provide an extra measure of holding power from the outside. Use of clamps depends upon the tubing material, the pressure of the system, vibrations and environmental conditions. For highly inflexible tubing, clamps are often necessary. But there’s also a downside to clamps. If installed incorrectly, clamps can actually induce leaks and failures. When installed properly behind hose barbs, the clamp is highly effective for providing additional grip on tubing. Still, it is worth investigating the pull-off and blow-off resistance of barbed fittings or couplings before you commit to clamps.
It’s all about fit and compatibility. Reliable connections for your system start with finding the proper combination of tubing and fittings/couplings. Matched properly with tubing or hose, the gripping and sealing power of fittings and couplings with a hose barb termination offers a connection with pull-off and blow-off resistance for most applications. Hose barbs provide a low cost and effective means for connecting many different types of tubes and hoses. To ensure a safe and secure system, determine how these critical elements work together to provide the best grip and seal for your application.
If you have any further questions about hose barbs or any CPC product, please complete the form, and a CPC representative will contact you.